Decrease in food intake during a meal following a protein preload could be related to acute hyperleptinemia.

Abstract

The aim of this study was to determine the relationships between the variations of plasma amino acids, glucose, insulin and leptin, and the decrease in energy intake following a high protein versus a high carbohydrate preload. The decrease in food intake observed with high protein preload could be related to changes in these plasma concentrations preceding a meal. Twelve male Wistar rats were intraorally fed with an isovolumic and isoenergetic preload of either carbohydrates (C100P0L0) or proteins (C14P55L31) 1 h before a 1 h meal of standard (P14) diet. Blood was collected by means of intra-jugular vein catheter 5 min before the P14 meal. Then plasma metabolites were measured. Ingestion of the protein preload induced a decrease in the intake of the subsequent P14 meal. Among the plasma metabolites the protein preload induced a rise in plasma AAs (leucine, and other BCAAS, phenylalanyne) and leptin level. In contrast glycemia and insulinemia were not different between groups. Additional measurements include the evolution of plasma glucose, insulin, glucagon, GLP-1 and leptin, at 0, 15, 30, 60 and 120 min after a preload of either a C76P14L10 or a C14P55L31 diet. Moreover, blood of the animals fed C14P55L31 preload was collected in acute condition and after a period of 2 weeks. Protein-induced satiety is related to a acute plasmatic hyperleptinemia preceding the following meal in rats.